The exact cause of his death has yet to be determined, but that certainly hasn’t stopped people from speculating about potential causes. First, there were reports that an overdose might have been to blame. Now, there are rumors that Piana might have died from using insulin, the hormone that regulates your body’s blood sugar. People who inject insulin and who already produce the hormone naturally can see their blood glucose levels drop dangerously low—and if they don’t ingest additional sugar to bring their blood glucose back up, the consequences can be fatal.

But first things first: It’s important to note that the medical examiner’s office tells us it hasn’t yet determined how and why Piana died.

“We have not finalized a cause and manner of death, so it sounds like the insulin issue is just a rumor,” Florida’s District Six Medical Examiner’s Office, which is currently conducting Piana’s autopsy, told Men’s Health.

Though the rumors about Piana’s death remain wholly unverified, it’s true that insulin use is on the rise among bodybuilders, according to Dr. Harrison Pope, M.D., a psychiatry professor at Harvard Medical School who’s conducted extensive research on substance abuse amongst bodybuilders. Piana himself was vocal about his use of insulin, going into detail about the practice in a YouTube video posted four years ago. He acknowledged that taking insulin can be “dangerous,” but said the danger is easily avoidable if you take the right amount of sugar.

Why would a bodybuilder be taking insulin, a hormone commonly associated with type I diabetes? In addition to regulating blood glucose levels, insulin also has anabolic properties, meaning it helps to grow your muscles.

“Insulin is widely used for its anabolic properties that, like steroids, aid in muscle growth,” Pope told Men’s Health. “Furthermore, it is undetectable in testing because insulin is already present in the body.”

Another reason insulin is so appealing is because of its apparent lack of side effects. He added that it wouldn’t “cause those hormonal changes you see with traditional anabolic steroids,” which include a deepening of the voice and extra body hair growth for females and the development of breasts, testicle shrinkage and loss of hair in males.

A study published in Current Sports Medicine Reports that looked at weightlifters who use insulin to supplement their weightlifting found that insulin use is on the rise—not only for the reasons listed above, but because it’s so easily accessible.

“It’s not a controlled substance, like other (performance enhancing drugs),” Pope said. “Insulin is readily obtainable.”

An overdose of insulin can cause hypoglycemia, which can lead to seizures, comas, neurological brain damage and death. While insulin overdoses are common, especially among those with diabetes, the likelihood of death as a result of an insulin overdose is actually rare—particularly in cases where the patient receives rapid medical treatment.

A study published in the International Journal of Clinical Pharmacology and Therapeutics looked at 160 cases of insulin poisoning and found that deaths from insulin poisoning were not only rare, they were also most often a result of deliberate overdose in an attempt to take one’s own life.

The study found that 89.4 percent of the reported cases were suicide attempts, 5 percent were accidental overdoses, 1.9 percent were criminal overdoses and the remaining 3.7 percent were unknown. Of the total number of cases, 94.7 percent made a full recovery, 2.7 percent experienced cerebral defects and just 2.7 percent died.

A study conducted by the British Journal of Sports Medicine looking into insulin abuse among bodybuilders drew similar conclusions. It found that insulin use was becoming very popular among bodybuilders—and that it becomes especially dangerous when a bodybuilder keeps their insulin use private.

As for Piana, his autopsy has yet to confirm his cause of death. What we do know is that he collapsed while his girlfriend, Chanel Jansen, was giving him a haircut. Jansen told People that she gave him chest compressions until an ambulance arrived, but that doctors told her he “was gone before he even hit the floor” as a result of a heart attack. He was placed in a medically-induced coma for two weeks before he died.